Much-need rain has begun to fall over Southern California, bringing relief to the drought-stricken region but also the threat of toxic runoff.

A portion of the Pacific Coast Highway in Los Angeles County was closed on Sunday afternoon due to mudflows as rain fell in parts of Southern California.

A major rainstorm sweeping through the Los Angeles area is threatening Southern California's recovery from this month's devastating wildfires, creating dangerous conditions that could include debris flows and mudslides.

Southern California is expecting up to an inch of rain in some parts, aiding the fight against wildfires but also causing landslides that threaten homes in Los Angeles area. NBC News' Steve Patterson reports on the anxieties residents face as they try to resettle.